Coil terminal



Aug. 31, 1937. L. E. S'EVISON COIL TERMINAL Filed June 25, 1954 INVENTOR. I gifieflj (fer/a0.

rm% AWw/z/ ATTORNEY.

Patented Aug. 31, 1937 2,091,798

UNITED STATES PATENT OFFICE COIL TERMINAL Luther E. Sevison, Toledo, Ohio, assignor to The Machined Parts Corporation, Detroit, Mich., a corporation of Michigan Application June 25, 1934, Serial No. 732,281 4 Claims. (01. 175-357) This invention relates to insulating caps such deposits accumulating on the outside of the cap, as used on ignition coils and similar electrical igcauses the secondary current to seek a path up nition apparatus, and it is the prime object of the and around the neck of the secondary terminal invention to provide a cap of insulating material socket and to short across to one of the priso designed and constructed that the distance or mary terminals, and I have, therefore, designed gap between the secondary terminal and the a cap which is moulded, preferably of bakelite, or primary terminals is materially lengthened; conother plastic material of high dielectric strength, sequently, any possibility or tendency of the and in which all metal inserts in the secondary secondary current to short to one of the pricircuit are eliminated, thereby increasing the mary terminals is minimized or entirely elimidistance or path of the electrical current between nated. the secondary and primary terminals, and provid- Another object is to provide a cap and terminal ing for a more efficient operation and economical assembly which insures a positive connection at construction. all times, which eliminates the usual metal inserts Referring now more particularly to the drawfound in conventional sockets and terminals, ing, the numeral 5 indicates a cylindrical metal 15 thereby simplifying the manufacturing and retube or shell which can be formed in any desired ducing the production cost. manner, and a bakelite cap 6 forms a closure for A further object is to provide simple and ecothe open upper end thereof, a groove 1 being nomical means for forming an electrical conmoulded in said cap, and the upper end of the nection between the secondary lead and the high shell is beaded and pressed into said groove for 20 tension cable, as Well as means for clamping the rigidly securing the cap thereto. end of the high tension cable in the terminal The cap 6 is formed as clearly shown in Figs. 1 socket. and 2 of the drawing, the projecting neck 8 of the A still further object is to provide means for cap having a slightly tapered cored socket 9, 5 positively sealing the coil cap to eliminate the internally threaded as at It] to receive the secondpossibility of moisture,dust or other foreign matary terminal H, said socket terminating in a ter entering the secondary terminal or terminal reduced passage 12 which opens to the downwardsocket. ly extending tubular extension I3 which is mould- With the above and other objects in view the ed integral with the cap.

present invention consists in the combination and Bosses M are moulded on the cap in spaced 30 arrangement of parts, hereinafter more fully apart relation, and hollow primary terminals l5 described, illustrated in the accompanying draware moulded in said bosses, and to which the priing, and particularly pointed out in the appended mary lead wires are adapted to be connected in claims, it being understood that changes may be the usual manner.

made in the form, size, proportion, and minor The iron wires l6 which form the core portion 35 details of construction, without departing from of the magnetic circuit of the coil project into the spirit or sacrificing any of the advantages of the tubular cap extension l3 and are encased in a the invention. nonconducting insulating tube H which is sur- In the drawingrounded by the secondary winding l8, said wind- Fig. 1 is a part sectional side elevation of an ing comprising a plurality of layers of a large 49 ignition coil showing my cap in connection therenumber of turns of fine wire separated by paper with. insulation, the margin of which is indicated at 19.

Fig. 2 is a top plan view. The primary winding 20 surrounds the secondary Fig. 3 is avertical sectional view of the terminal, winding, and this primary winding is in turn illustrating the manner of connecting the high surrounded by outer laminations of magnetic 45 tension cable with the secondary lead. material 2| in the usual manner.

Fig. 4 is a plan thereof. In assembling the coil I first pour wax in the In the conventional ignition coil, a brass insert bottom of the coil assembly, after which I turn or ferrule is moulded into the center or secondary it end for end and thread the lead wires 22, 23,

50 terminal socket, and as this insert is from oneand 24 into the cap; I then place the assembly in 50 half to one inch long, the path of the electrical the shell, pour wax in the shell around and over current between the secondary and primary terall the coil assembly, thereby sealing it into minals is shortened accordingly. Moisture gaththe shell, press the cap firmly in position, and ering in the inside of the secondary terminal secure it by rolling the upper edge of the shell socket, and grease laden with dust or carbon into the groove 1 in the cap. These primary 55 lead wires 22 and 23 can then be soldered or otherwise secured to the terminal screws IS. The secondary lead wire 24 is connected in a different manner, the .end section, which extends into the cored socket 9, being crushed or matted down as shown at 25 in Fig. 3, so as to prevent disengagement and to further provide a suitable contact.

The secondary terminal H is also moulded and is formed as clearly shown in Fig. 3 of the drawing, the upper end being preferably shouldered and knurled as at 26, the reduced lower end section being tapered and is threaded at a point intermediate its length to engage the threaded section of the cored socket 9 so that it can be firmly secured in position, a rubber washer 21 being interposed between the shoulder on the terminal and the upper end of the neck 8, and forms a tight dust and moistureproof joint.

A centrally disposed tapered passage 28 is provided in the upper .end of the terminal ll, said passage opening into a reduced passage 29 which extends through the terminal, and I wish to direct particular attention to the fact that there are no metal inserts or ferrules onthis terminal I! or in the socket 9 in which it is inserted.

The end section 30 of the high tension cable 3| is bared as shown in Fig. 3 of the drawing, and the tapered passage 28 is of predetermined size so that when the high tension cable is inserted,

30 it must be forced and twisted around several times to force it to position, so that the end of the insulation bottoms on the shoulder of said passage.

This causes the wall of the cable insulation to become compressed in the passage, and to form a dust and moistureproof seal.

When the high tension cable has been forced to proper position, the bared section 30 will extend downwardly with the end projecting beyond the end of the terminal, the separate strands of this end section being spread to form an electrical connection with the secondary lead wire which is crushed in the bottom of the socket 9, and when the terminal H is screwed in the socket 9 of the cap, the end strands of the bared wire 3| are firmly pressed against the crushed end 25 of the secondary lead wire 24, forming a positive electrical connection, said strands being clamped between the bottom of the socket and the end of the terminal, thereby rigidly securing the high tension cable in position, and eliminating the possibility of its being pulled out and breaking the electrical connection.

This construction positively seals the coil cap from the sealed high tension cable insulation joint to the end of the secondary terminal without possibility of moisture, dust, or foreign conducting matter reaching the chamber, the rubber washer 21 sealing the joint between the end of the cap neck 8 and the shoulder on the secondary 0 terminal ll, thus the entire socket 9 is positively sealed with no possibility of moisture or other foreign elements altering the insulating features which have been created.

It will, of course, be understood that the wind- 5 ing, assembly, etc. of the coil is immaterial and that any desired method may be used, as this invention is directed to the insulating and sealing of the cap, secondary terminal, the connections, and manner of securing.

From the foregoing description it will be obvious that I have perfected a very simple, practical, efi'icient, and economical cap for ignition coils and similar electrical equipment.

What I claim is:

1. In an ignition coil the combination of an insulating member having a wholly non-conductive, tapered and internally threaded socket therein, a shouldered wholly non-metallic, tapered and threaded secondary terminal adapted for engagement in the socket, a tapered passage in said terminal, a high tension cable adapted to be inserted in said passage to form a dust and moisture-proof seal thereat, and a resilient washer interposed between the top of the insulating member and the shoulder on the terminal to form a dust and moisture-proof seal thereat.

2. In an ignition coil the combination of an insulating cap member having a wholly non-conductive, tapered and internally threaded socket therein and terminating in a reduced passage adapted to accommodate the secondary lead of the coil, a wholly non-metallic, tapered and threaded shouldered secondary terminal adapted for engagement in the socket, and provided with a tapered passage therethrough, a high tension wire adapted to be mounted in said passage and forming a dust and leakproof seal thereat, the end of the wire being bared and projecting beyond the end of the terminal to form a contact with the secondary lead of the coil, and a washer interposed between the upper end of the cap and the shoulder on the secondary terminal to form a leakproof joint thereat.

3. In an ignition coil, the combination of an insulating member having a wholy non-conductime, tapered and internally threaded socket therein, a wholly non-metallic, tapered and externally threaded, shouldered and hollow terminal adapted for engagement in the socket, a

high tension wire adapted to be mounted in said terminal, the end of said wire being bared to form a connection with the secondary lead of the coil, and a resilient washer interposed between the top of the insulating member and the shoulder on said terminal.

4. In an ignition coil, the combination of an insulating cap having a wholly non-conductive, tapered and internally threaded socket therein, a wholly non-metallic, tapered and externally threaded terminal adapted for engagement in the socket, and formed with an external shoulder and a shouldered, tapered passage therethrough, a high tension wire mounted in said passage with its bared end projecting beyond the .end of said terminal for engagement with the secondary lead of the coil, and a resilient washer interposed between the upper end of the cap and the external shoulder on the terminal to form a tight, leakproof joint thereat.

LUTHER E. SEVISON. 

